Whilst you could invest in any number of fixed rate bonds - to mature at different times I wouls consider a number of other options; you don't mention how old you are? I would suggest that you spend part of your inheritance on travel whilst you are fit and well; also on any home improvements that you want; also give some away to your family - if you have children setting up home - they may as well have the benefit of some help now rather than later - and you could see their enjoyment whist they are young.

My wife and I have just received a £75,000 inheritance.  We have paid of our mortgage and have no debts, we also have sufficient savings not to need immediate access to this money.  We have both recently taken out ISA's.  We are looking for a means of safely depositing this money, with a good rate of interest, can you suggest types of account?